1. Field of the Invention
The present invention relates to the formation of circuit board assemblies and, more particularly, to the bonding of a flex circuit to a printed circuit board.
2. Description of the Related Art
Anisotropic conductive film (ACF) bonding is a technology that is used to attach flex circuits to printed circuit boards (PCBs). ACF bonding typically includes applying an ACF bond material between a PCB and a flex circuit that is to be bonded to the PCB. Once the ACF bond material is applied between the PCB and the flex circuit, an increased pressure and an increased temperature are applied to the PCB and the flex circuit. That is, the layer stack formed from the PCB, the ACF bond material, and the flex circuit are effectively “sandwiched” and subjected to an increased pressure and an increased temperature.
Often, opposing ACF support heads may be used to apply force and, hence, an increased pressure to the layer stack. One of the opposing ACF support heads may be heated such that an increased temperature may be applied to the layer stack. If the opposing ACF support heads come into contact with components of the PCB, the relatively high forces and pressures applied by the opposing ACF support heads may damage such components and, hence, adversely affect the integrity of and the performance of an overall PCB assembly that includes the PCB. As a result, the area on the PCB onto which the opposing ACF support heads are arranged to apply relatively high forces and pressures are generally devoid of components.
The footprint associated with opposing ACF support heads may be relatively large. That is, an ACF support head may essentially require that a significant amount of real estate on a PCB be substantially devoid of components in order for a flex circuit to be bonded to the PCB without compromising the integrity of and the performance of the PCB. Because real estate on a PCB is typically at a premium, leaving open space on the PCB in order to accommodate an ACF support head may be impractical, if not impossible.
To provide for open space on a PCB in order to accommodate an ACF support head, the size of the PCB may be increased. However, increasing the size of a PCB may be expensive and unworkable. By way of example, if a PCB is intended to fit in a chassis or a housing of a particular size, it may not be possible to increase the physical size of the PCB in order to provide open space. In addition, increasing the size of a PCB goes against the overall trend of tightly spacing components such that a PCB may be sized to be no larger than necessary to accommodate all desired components
Therefore, what is needed is a method and an apparatus that allows an ACF bonding process to be used to bond a flex circuit to a PCB without applying an increased pressure and an increased temperature to components of the board. That is, what is desired is a method and an apparatus for using an ACF bonding process to bond a flex circuit to a PCB without compromising the integrity of components on the PCB, and without substantially requiring excess open space on the PCB.